On graviton propagation in curved space-time background

Equation describing propagation of gravitational waves (GW) over arbitrary curved space-time background is analyzed. A new term, which is absent in the conventional homogeneous and isotropic Friedmann cosmology, is found. Some examples of realistic metric, where this new term manifests itself, are presented. Possible implications to very low frequency GW are briefly discussed.Comment: 9 page

Numerical deterination of crack initiation moment in Charpy specimens and side-grooved specimens

Було проведено чисельне моделювання ударних випробувань зразків Шарпі та зразків з бічними надрізами у тривимірній постановці методом скінченних елементів з використанням моделі пошкоджуваності матеріалу Гарсона-Твергарда-Нідлмана (GTN). Визначено моменти зародження тріщини всередині зразка та на їх бічній поверхні. Проведено чисельне моделювання розповсюдження тріщини при різних механізмах руйнування (крихке, квазі-крихке, в’язке) що відповідають різним температурам випробування. Проведено аналіз впливу бічних витяжек на кінетику розповсюдження тріщини у зразках.Purpose. The object of the presented work is the finite element analysis of Charpy impact tests in the two-dimensional and three-dimensional formulations. Design/methodology/approach. Charpy specimens impact tests are one of more simple and inexpensive method to determine the mechanical properties of materials. The results of these tests can be used to estimate the strength and durability of large-scale structures. Numerical simulation of Charpy specimens impact test can give more information about the features of crack initiation and propagation in materials under dynamic loading. Findings. Numerical modelling of Charpy specimens impact tests was performed using Gurson–Tvergaard–Needleman (GTN) damage material model. Local approach to fracture allows to obtain crack initiation point data inside the specimen and on an edge side of the specimen. Using variable parameters of GTN model one can simulate crack initiation and propagation under different fracture mechanism. Present work describes an estimation of the crack initiation point under brittle, ductile, quasi-brittle fracture mechanisms using GTN model. Originality/value. The results of numerical modelling of Charpy specimens impact test can be used to evaluate the strength and life time of construction elements.Было проведено численное моделирование ударных испытаний стандартных образцов Шарпи и образцов с боковыми надрезами в трехмерной постановках методом конечных элементов с использованием модели повреждаемости материала Гарсона-Твэргарда-Нидлмана. Определены моменты зарождения трещины внутри образцов и на их боковой поверхности. Проведено численное моделирование распространения трещины при различных механизмах разрушения (хрупкое, квази-хрупкое, вязкое), соответствующих различным температурам испытаний. Проведен анализ влияния боковых утяжек на кинетику распространения трещины в образцах

Impact of self-regulation methods on the psycho-emotional state of future teachers

The authors remark the necessity to develop the psycho-emotional self-assessment and self-regulation capability of future teachers during the period of vocational training at the university. The training program on the development of students' psycho-emotional self-regulation is presented. The possibility of training practice on behavior and activity self-regulation development as one of the phenomena of a person’s mental life is investigated via methods of questioning, operational control of neuropsychic activity (electrocutaneous resistance), and the Luscher tes

Results of a search for 2β\beta-decay of 136^{136}Xe with high-pressure copper proportional counters in Baksan Neutrino Observatory

The experiment for the 2$\beta$-decay of $^{136}$Xe search with two high-pressure copper proportional counters has been held in Baksan neutrino observatory. The search for the process is based on comparison of spectra measured with natural and enriched xenon. No evidence has been found for 2$\beta$(2$\nu$)- and 2$\beta$(0$\nu$)-decay. The decay half lifetime limit based on data measured during 8000 h is T$_{1/2}$$\geq8.5\cdot10^{21}$yr for 2$\nu$-mode and T$_{1/2}$$\geq3.1\cdot10^{23}$yr for 0$\nu$-mode (90%C.L.).Comment: 9 pages, 8 figures; talk at the NANP'05 Conference; submitted to Phys. At. Nuc

New limit on the mass of 9.4-keV solar axions emitted in an M1 transition in 83^{83}Kr nuclei

A search for resonant absorption of the solar axion by $^{83}\rm{Kr}$ nuclei was performed using the proportional counter installed inside the low-background setup at the Baksan Neutrino Observatory. The obtained model independent upper limit on the combination of isoscalar and isovector axion-nucleon couplings $|g_3-g_0|\leq 1.69\times 10^{-6}$ allowed us to set the new upper limit on the hadronic axion mass of $m_{A}\leq 130$ eV (95\% C.L.) with the generally accepted values $S$=0.5 and $z$=0.56.Comment: 5 pages, 2 figures, Proceedings of the 10th Patras Workshop on Axions, WIMPs and WISP 29 June - 4 July 2014, CERN, Geneva, Switzerlan